Research on India’s lion-tailed macaques shows why humans need to rethink habitat fragmentation

Often a defining feature of any landscape, a “boundary” as perceived by humans, is almost never seen as a limit by other species. On the other hand, a road or a series or electricity poles, which might not be considered hard boundaries by humans, might as well be the end of land to others.

Human activities around the world have transformed primary landscapes, whether forest or marsh lands or mangroves, into a patchwork of fragments. Today, if you drive a 100 kms in any direction in most areas, you will observe a mosaic of forests, crop land, plantations, human habitation, industrial areas and the like. And all this transformation has taken place with only one species in mind – humans.

Post landscape alterations – most of which threaten the existence of wildlife species – conservation research and actions have been tailored to circumstances and reality of protected areas and have seldom addressed the importance of mosaic landscapes around such protected areas and complex interactions within them. Research has been increasingly illustrating the intensity and varieties of use of human dominated landscapes by several species, such as leopards and elephants.

A recent paper reiterates this point by presenting evidence from modified landscapes such as tea-coffee-forest-fragmented matrix of Valparai plateau in the Anamalai Hills. It illustrates the crucial role of natural and anthropogenic habitats vis-a-vis three charismatic species, Asian elephants, leopards and lion-tailed macaques.

Ananda Kumar, a scientist with the Mysore-based Nature Conservation Foundation and the lead author of the paper, has been studying interactions between wildlife and humans in patchwork landscapes. According to him, the Valparai experience shows unique considerations (landscape, behaviour, ecology, nature of human habitations), have to be included while innovating conservation solutions. While habitat generalists (elephants or leopards) often adapt behaviourally and ecologically to modified landscapes, habitat specialists, such as lion-tailed macaques could find survival harder, with increasing anthropogenic pressures and loss of habitats.

“We always try to go from solution to problem and that’s wrong,” said Kumar. “People need to look at needs and requirements of both wildlife and people. In most places what people want, what the department (forest) does and what scientists do is a mismatch. There has to be clarity among these things that can facilitate an inclusive approach rather than exclusive.”

Fragmented habitat

Globally, forested areas are increasingly under pressure and either being completely removed or reduced to fragments. But, if imaginatively managed, fragments can host and support some species and facilitate their movement across human areas safely.

Asian elephants, for instance, are known to use commercial plantations such as tea, coffee, rubber, cardamom and oil palm plantations, which are often mixed with elephant landscapes. “These habitats are extremely important for movement of elephants; and often, they act as refuges, which provide food and shelter in modified landscapes,” said the paper.

Valparai (Anamalai Hills), for instance, which holds the second largest Asian elephant population in India, is spread across 220 square km of tea, coffee and eucalyptus plantations, interspersed with rainforest fragments. In spite of the dense patchwork, the landscape supports around 120 elephants among 70,000 people, with elephants primarily using the plantations to move across the rainforest fragments and the surrounding protected areas. This, or any landscape, has numerous stakeholders, users and providers. This complex profile needs to be essential to conservation planning.

“Let’s take the example of coffee – it might not look like it but it is as good as a forest for elephants. It has grass, water and shade,” said Kumar. “Monoculture acacia or eucalyptus plantations have secondary vegetation, which is good for elephants. Monoculture refuges are heavily used by elephants in Hassan regions. And unless we start seeing land from that angle, we can’t maintain a balanced approach. Right now – we think like this – ‘elephants are supposed to be in forest areas, they have no business here’. This is how we lose ground for animals.”

The example of elephants is different from the case of the lion-tailed macaques. The difference being between habitat generalists (elephants) and specialists (lion-tailed macaques), whose survival is dependent on a specific type of habitat, in this case a tropical rainforest. On the Valparai Plateau, their presence is restricted to these isolated rainforest fragments, islands in a sea of tea and coffee.

“For a species like the LTM [lion-tailed macaques] life in a forest fragment is even harder,” said Ashni Dhawale, a graduate student from the National Centre for Biological Science, Bangalore, currently studying lion-tailed macaques behavioural ecology. “Known as the only truly arboreal macaque species, the LTM moves primarily through the rainforest canopy where it is safer from terrestrial predators and, being mainly frugivorous, closer to its main source of food, rainforest fruits. However, in forest fragments the vegetation is often degraded, leading to a sparse and disconnected canopy. Such disturbances cause an increased use of the ground substrate by the LTM where it is vulnerable to various factors such as provisioning by humans.”

When male lion-tailed macaques reach sexual maturity, they disperse from the natal troop – an evolutionary trait that has evolved in many species, to avoid inbreeding among relatives. Dispersal between forest fragments through a matrix of anthropogenic habitats, for a small-bodied species like the lion-tailed macaques, may be near impossible, leading to a decrease in dispersal and thus the possibility of inbreeding and dramatic changes in social organisation in these isolated populations, with unknown consequences. From elephants to lion-tailed macaques to humans, the profile of a landscape is astoundingly dynamic.

“The idea is to see a habitat as we use it but as how other species think of it, how does it alter their decisions, take note of their adaptations, their ability to cope with pressures in modified habitats,” said Kumar. “Clearly, specialists are unlikely to survive. Some species can adapt to changes but often not fast enough. Even if they can adapt, and we remove all rainforest areas, they will disappear. Rainforests are there, therefore, they are there. And we don’t know the threshold of disturbance below which they can’t exist. That’s tricky. We have very little idea of the behaviour of species, food, ecology.”

Behavior change on both sides

Dhawale’s work on lion-tailed macaques is shedding light on this sparsely researched topic, and on the minute, nuanced ways that the human lifestyle is bending the way other species live, often to their peril and eventual extinction. Dhawale’s research is, in fact, showing the behavioral adaptations lion-tailed macaques are going through.

One of the biggest drivers of behavioural changes displayed by the lion-tailed macaques resident in human-dominated landscapes is the presence of human-use food sources. Human-use foods are known to be highly nutritious, easily and readily available in high quantities; these factors, coupled with a degradation of natural food resources in forest fragments lead to shifts in diet. “This is especially so for many macaque species, most of which have already become commensal with humans across the globe,” explained Dhawale. “The LTM has also begun to show shifts in diet, visiting human habitation at a rate of more than 0.43 times a day and raiding homes, especially kitchens.”

Although seemingly advantageous to the lion-tailed macaque, a shift in diet from their natural food resource to human-use foods may have many unforeseen consequences including strain on their digestive systems and increased susceptibility to disease and parasites. One of the intriguing behavioral changes involve their resting time, which is directly proportional with their consumption of human-use foods. “Such a trend may lead to a decrease in affiliative social interactions among individuals in a troop, an important aspect required for the long-term survival of a social animal,” said Dhawale.

The lion-tailed macaques in these populations already show nuanced changes in their social behaviour; for example, primates groom each other extensively to maintain hygiene and increase social bonds between individuals, much like traditional lice-checks among human family members. In lion-tailed macaques, individuals develop a pairwise bond with members of their troop over the long- and short-term, maintained through the act of grooming. “In cases where human-use food is available, however, LTMs show a ‘break’ in these bonds, choosing to groom individuals that provide other benefits such as higher dominance status, which is often directly associated with privileged access to food,” noted Dhawale’s research. Such changes in social organisation can potentially lead to a decrease in social cohesion, and consequently, an increase in aggression and noncooperation, which is disadvantageous in many ways to social animals.

Kumar, who has worked with elephants for several years, recounts an experience from Sathyamangalam protected area, where they were observing a makhna (tusk-less male elephant) and one tusker elephant. “During the day time, they were far away from each other but together in night when they would go to eat the banana crop,” said Kumar, who was intrigued by this temporary association.

What they observed was they at night, the tusker lifted the electric wire with its tusks till it broke, then they both entered the farm. “But the question was, what was the benefit for the tusker? asked Kumar. “Makhna definitely had the benefit. So it turned out that the makhna stood between people and the crops. He was less bothered of his own safety. There was this amazing sense of collaboration. They are a thinking species and this is a problem-solving behaviour. If you are dealing with intelligence then how can you just put up a fence and brush your hands off.”

The point Kumar makes is of context in problems, which in this case, refers to circumstances in the field, species behaviour, human behaviour, nature of conflicts etc. That just putting up an electric fence to demarcate areas where wildlife needs to roam does not work. Valparai is an exceptional landscape in that it has shown how conservation can, somewhat ideally, work when locals, science and the government come together. Erecting lines and fences, and digging trenches only begins to deepen the differences.

“We can’t have clear demarcated zones everywhere,” said Kumar. “If there is a wild elephant in Bengaluru then yes, they have to be moved out. But what about a coffee plantation next to a rainforest? There you can’t say that they can’t be seen ever. That is a coexistence zone.”

This article first appeared on Mongabay.